Unless otherwise indicated herein, the description provided in this section is not itself prior art to the claims and is not admitted to be prior art by inclusion in this section.
Various types of hearing prostheses provide people with different types of hearing loss with the ability to perceive sound. Hearing loss may be conductive, sensorineural, or some combination of both conductive and sensorineural. Conductive hearing loss typically results from a dysfunction in any of the mechanisms that ordinarily conduct sound waves through the outer ear, the eardrum, or the bones of the middle ear. Sensorineural hearing loss typically results from a dysfunction in the inner ear, including the cochlea where sound vibrations are converted into neural signals, or any other part of the ear, auditory nerve, or brain that may process the neural signals.
People with some forms of conductive hearing loss may benefit from hearing prostheses such as hearing aids or electromechanical hearing devices. A hearing aid, for instance, typically includes at least one small microphone to receive sound, an amplifier to amplify certain portions of the detected sound, and a small speaker to transmit the amplified sounds into the person's ear. An electromechanical hearing device, on the other hand, typically includes at least one small microphone to receive sound and a mechanism that delivers a mechanical force to a bone (e.g., the recipient's skull, or middle-ear bone such as the stapes) or to a prosthetic (e.g., a prosthetic stapes implanted in the recipient's middle ear), thereby causing vibrations in cochlear fluid.
Further, people with certain forms of sensorineural hearing loss may benefit from hearing prostheses such as cochlear implants and/or auditory brainstem implants. Cochlear implants, for example, include at least one microphone to receive sound, a unit to convert the sound to a series of electrical stimulation signals, and an array of electrodes to deliver the stimulation signals to the implant recipient's cochlea so as to help the recipient perceive sound. Auditory brainstem implants use technology similar to cochlear implants, but instead of applying electrical stimulation to a person's cochlea, they apply electrical stimulation directly to a person's brain stem, bypassing the cochlea altogether, still helping the recipient perceive sound.
In addition, some people may benefit from hybrid hearing prostheses, which combine one or more characteristics of the acoustic hearing aids, vibration-based hearing prostheses, cochlear implants, and auditory brainstem implants to enable the person to perceive sound.
A hearing prosthesis may include an external unit that performs at least some processing functions and an internal stimulation unit that at least delivers a stimulus to a body part in an auditory pathway of the recipient. The auditory pathway includes a cochlea, an auditory nerve, a region of the recipient's brain, or any other body part that contributes to the perception of sound. In the case of a totally implantable medical device, the stimulation unit includes both processing and stimulation components, though an external unit may still perform some processing functions when communicatively coupled or connected to the stimulation unit.
A recipient of the hearing prosthesis may wear the external unit of the hearing prosthesis on the recipient's body, typically at a location near one of the recipient's ears. The external unit may be capable of being physically attached to the recipient, or the external unit may be attached to the recipient by magnetically coupling the external unit and the stimulation unit.
A hearing prosthesis may have a variety of settings that control the generation of stimuli based on detected sounds. Such settings can include settings of a filter bank used to filter the received audio, a gain applied to the received audio, a mapping between frequency ranges of received audio and stimulation electrodes, or other settings. Such settings can be controlled to improve a recipient's ability, based on stimuli received from the hearing prosthesis, to discern speech or to perceive some other information. For example, settings of a filter bank can be controlled to remove noise from a detected audio signal that includes speech. Such settings may be controlled based on the experience of a recipient or based on properties of an audio environment of the recipient. For example, an audiologist could control the settings based on a recipient's description of a noisy environment that caused the recipient to experience difficulty understanding speech.